Effect of ventilator circuit changes on ventilator-associated pneumonia: a systematic review and meta-analysis.

BACKGROUND: Recent guidelines concerning prevention of ventilator-associated pneumonia recommend that ventilator circuits should not be changed routinely, but in practice circuit changes at regular intervals persist.
METHODS: We searched the MEDLINE, EMBASE, and SCOPUS databases and reviewed citations to identify articles that reported the results of randomized controlled trials and sequential comparison studies that provided a clearly defined intervention of circuit changes (interval > or = 2 d) and the outcome measure of the development of ventilator-associated pneumonia in mechanically ventilated adult patients. Both authors independently assessed the validity of the included studies, and extracted data using a pre-designed data-collection form. We used a random-effect model to combine data from studies that compared circuit changes every 2 days versus every 7 days, and circuit changes at regular intervals versus no routine circuit change.
RESULTS: The search yielded 10 reports, which included 19,169 patients. Compared to patients exposed to circuit changes every 7 days, patients who received circuit changes every 2 days had a higher risk of ventilator-associated pneumonia (odds ratio 1.928, 95% confidence interval 1.080-3.443). Compared to no routine circuit change, changing the ventilator circuit at a 2-day or 7-day interval was associated with an odds ratio of 1.126 (95% confidence interval 0.793-1.599). There was a trend of reduced risk of pneumonia as circuit-change intervals were extended.
CONCLUSIONS: Frequent ventilator circuit changes are associated with a high risk of ventilator-associated pneumonia. No routine circuit change is safe and justified. Hospital infection-control policies and bedside practitioners should translate the evidence into clinical practice, if they haven't done so already.